There is disclosed a two-wheeled motor vehicle in which a canister for temporarily adsorbing evaporated fuel in a fuel tank is mounted and the evaporated fuel is supplied from the canister to an engine intake system (see Patent Document 1, for example). When a canister is mounted in a straddle type vehicle such as a two-wheeled motor vehicle or the like, the design of the vehicle body is restricted to secure the mount space of the canister and also the vehicle body must be large in size.
A method of introducing evaporated fuel in a fuel tank into a crank chamber after the evaporated fuel is passed through oil in an oil pan in the crank chamber and introducing the evaporated fuel to an engine intake system together with blow-by gas under operation of an engine is disclosed as a method of using no canister (see Patent Document 2, for example).